I just put a fishman ellipse blend in my Martin A/E. I'm having some confusion here. I don't know where to attach the wire from the piezo ? The preamp works ,I plugged it in and was picking up the mike on the pre amp.

Both wires go directly to the preamp. The lead from the UST goes to the silver terminal with two screws. You may have just bypassed the whole blend and gone straight to the switchjack, or am I confusing my systems.

No. That pic is for a stereo wiring, and it doesn't seem to be labeled correctly. You'd want the second pickup on the ring tab (second shortest tab) and the lead from the battery negative connected to the switch tab (longest tab).

Its my understanding that the Ellipse Blend is an onboard blender which is usually wired for mono out. There wouldn't be anything wired to the ring tab unless its custom wired for stereo out. In the case of stereo out, you'd need a stereo cable to access both signals. A mono cable would short any signal on the ring tab to ground.

It seems to me that everything (including the Switchjack connections) for this system should be pre-wired except for the leads from the undersaddle pickup. Those leads must be threaded through the hole in the bridgeplate (when the pickup is installed) before they can be connected to the onboard preamp.